1,721,078 research outputs found
Ruolo del calcio e della vitamina D nell'epitelio intestinale
No full textL’ epitelio intestinale rappresenta la prima superficie di contatto tra i nutrienti, derivanti dalla digestione degli alimenti, e il nostro organismo. E’ indubbio perciò che le stesse cellule intestinali siano fortemente influenzate dall’ interazione con alcuni componenti degli alimenti che possono modulare processi cellulari come proliferazione, differenziamento e apoptosi, intimamente coinvolti nella progressione e/o regressione del fenotipo tumorale. Tra i nutrienti direttamente coinvolti in questo tipo di interazioni, il calcio e la vitamina D giocano un ruolo sicuramente preminente. Recenti studi epidemiologici hanno infatti messo in evidenza come l’incidenza di tumori del colon, tra le forme tumorali più diffuse e seconda causa di mortalità per tumore nelle società industrializzate, sia inversamente proporzionale all’assunzione con la dieta di calcio e vitamina D, presente nel nostro organismo nella sua forma attiva, l’ 1,25(OH)2D3. In realtà l’effetto del calcio e della vitamina D dipende dallo stato differenziativo delle stesse cellule intestinali. L’aumento dell’assunzione di calcio con la dieta ha un effetto pro-differenziante, chemopreventivo negli enterociti sani che esprimono il CaSR (Calcium Sensing Receptor), mentre nelle cellule che vanno incontro ad una trasformazione pre-neoplastica e pre-maligna ha un effetto di promotore della carcinogenesi, a causa delle parziale o totale mancanza del CaSR. La vitamina D esplica un’azione chemopreventiva mediante l’interazione con il calcio sia a livello di attivazione/inibizione delle vie antiproliferative/pro-differenzianti, sia favorendo l’espressione del CaSR. In questo contesto resta da comprendere il possibile ruolo esercitato da altri componenti degli stessi alimenti, come per esempio le proteine, nel determinare il fenotipo normale o patologico
Morpho-physiological correlations in presence of an excess of nutrients in a Caco2/HT29 co-culture
No full textThe study of the interactions between nutrients and intestine requires in vitro models mimicking as close as possible both the morphology and the physiology of the human intestinal epithelium. Many experimental difficulties hampered in establishing a physiological long-term experimental model starting from primary cultures of normal small intestinal and colon cells. For this reason, a Caco2/HT-29 (70/30) co-culture was set up in our lab starting from the differentiated parental cell populations. Both cell lines originate from a human colon adeno carcinoma but, when differentiated, Caco2 cells are mostly absorptive and do not secrete mucus, while HT-29 cells are a heterogeneous population, comprising scattered enterocyte elements and mucus secreting cells. The co-culture represents an in vitro model of the small human intestine as it concerns final digestion and absorption of digested foods. This experimental setting allowed also studying the effects induced by an excess of nutrients by changing the frequency of the medium administration.
Two parallel experimental groups were cultured: the standard group (ST) and the excess group (EX). In ST group the culture medium was changed every four days, whilst in EX group on alternate days from confluence (T0). Co-culture was harvested at T0 and at 3, 7, and 15 days post-confluence (T3, T7, and T15, respectively). In comparison with the ST group, the EX group revealed a maintenance in the number of microvilli, an increase in follicle like-structures and mucus production, and a decrease in the number of tight junction. The specific activity of Alkaline Phosphatase, Aminopeptidase N, and of Dipeptidyl Peptidase-IV, known markers of intestinal and enterocyte differentiation, progressively increased. At T15 in the EX group an increased permeability to large molecules evidenced by the Transepithelial Electrical Resistance and the Lucifer yellow permeability was evident. At the same time, the level of ROS and NO production increased as well as of interleukin-6 and interleukin-8, all markers representing a low grade of inflammation.
These results agree with the morpho-functional features associated to the intestine of overweight/obese animals. The two in vitro intestinal models represent the possibility to study the patho-physiology of the interactions between nutrients and human gut. Next step will be the completeness of the co-culture models with the microbiota
Valutazione dell’attività antiossidante di digeriti in vitro di miscele peptidiche bioattive derivanti dalla caseina bovina in colture di cellule intestinali e osteoblasti umani
No full textI caseinofosfopeptidi (CPP) legano ioni quali Fe2+ e Ca2+ ed esercitano attività antiossidante in soluzione, tramite scavenging dei ROS e chelazione di Fe2+. Lo scopo del presente lavoro è studiare per la prima volta le proprietà antiossidanti di miscele purificate e semi purificate di CPP, dopo digestione in vitro, nella co-coltura Caco2/HT-29 70/30 e nella linea cellulare SaOS2 quali modelli in vitro di intestino e osteoblasti, rispettivamente. CPP MD, derivante dalla β-caseina bovina, CPP DMV, derivante dalla α-caseina bovina e CP, contenente sia CPP che altri peptidi, sono stati analizzati tal quali e dopo metabolizzazione intestinale (MI). I risultati ottenuti sono stati espressi come incremento % dell’attività antiossidante rispetto alla Vitamina C. In presenza di Fe2+: DMV e CP mostrano un incremento del 277±11 e 342±9% nelle cellule intestinali; MI CP del 103±9% negli osteoblasti (P<0,01). In presenza di ROS: DMV e CP mostrano un incremento del 158±15 e 216±14% nelle cellule intestinali, mentre tutti i digeriti metabolizzati mostrano un incremento dal 227±15% al 766±3 (P<0,01) negli osteoblasti. I risultati confermano il potenziale antiossidante dei peptidi della caseina anche a livello cellulare e suggeriscono una possibile applicazione nelle patologie ossee
Modelli cellulari in vitro per lo studio dei meccanismi alla base delle funzioni intestinali
No full textCasein phosphopeptides : from milk to nutraceutical
Full text linkMilk and dairy products are known sources of bioavailable calcium for its association with casein, whose proteolysis produces caseinphosphopeptides (CPPs). CPPs are phosphorylated peptides able to bind and solubilise calcium. In human intestinal tumor cells differentiated in vitro toward an enterocityc phenotype, they also induce a calcium uptake. Moreover, in human in vitro osteoblasts, CPPs favour the mineralization of the extracellular matrix. CPPs can differently affect proliferation and apoptosis in differentiated and /or tumor intestinal cells. Due to all these properties, CPPs may be considered as potential nutraceutical/functional food
Phosphopeptides of casein and calcium uptake
No full textCasein phosphopeptides (CPPs) originate from both in vitro and in vivo
casein hydrolysis and are characterized by a sequence of five amino acids highly
conserved, constituted by three phosphorylated serines and two glutamic acids and
known as “acidic motif”. A role for this highly polar acidic domain has been
attributed in stabilizing the colloidal calcium phosphate of casein micelles, and, in
the case of casein phosphopeptides, in the ability to bind and solubilize calcium
ions, thus preventing the formation of amorphous calcium phosphate. In milk, the
physico-chemical form of calcium plays an important role in casein micelle
stability, and contributes to high calcium availability. Also CPPs display the
ability to form aggregates with calcium ions, and these aggregates have been
demonstrated to represent the bioactive form of CPPs. Till their discovery, CPPs
were hypothezed to act as promoters of calcium absorption by the human gut.
Although experiments carried on in animals or in intestinal preparations were not
conclusive, a CPP induced calcium uptake by the human intestinal tumour lines,
HT-29 and Caco2, differentiated in vitro, was proved. This CPP bioactivity is
correlated to the cell differentiation degree and to the presence of the “acidic
motif”. The notion that the higher is the fraction of bioavailable calcium, the
higher is the amount of the mineral for the specialized tissues, as bone and teeth,
has attracted numerous researchers; indeed data available seem to confirm this
possibility. Taken together and besides some controversial results, above all in
humans, CPPs may be undoubtedly considered as potential nutraceutical and/or
functional food. The potentiality of casein phosphopeptides could be of practical
application for their presence in dairy products frequently consumed by the
Western population. Moreover, their solubility in water allows to use these
peptides as an easy to transfer ingredient in food
Mediterranean diet: functional foods and physical activity, benefits for human health
No full textThe Mediterranean diet is a well recognized life and food habits having relevantassociation with a reduced mortality caused by diseases such as cardiovascular disease,obesity, diabetes, cancer and neurodegenerative disorders. The importance of a healthybalanced diet lies on the fact that benefits come from the presence and the interaction ofalmost all the nutrients with which it is composed. It is a matter of fact that singlenutrients can behave differently from what it is observed when they are all mixedtogether with interactive possibility. Under this perspective, the Mediterranean diet isboth composed by a great number of single functional food and, as a whole, it is a resultof a balance between the single nutrient properties, as evidenced by its great capacity toprevent all the chronic degenerative disorders above mentioned. Among the functionalfood present in the Mediterranean diet are cereals, legumes, fruit and vegetables, nuts,olive oil as the prevalent fats for dressing, red wine in moderate quantity and consumed atmeals, fish and poultry as the main source of protein and polyunsaturated/saturated fats,modest quantity of dairy products, spices. Since the Mediterranean diet is a dietarypattern common to more than one country in the Mediterranean basin, some differencescan be found between the food consumed by the populations. The health benefits comingfrom the food of the Mediterranean diet resides on the presence of bioactive compoundssuch as polyphenols, carotenoids, phytosterols, fibers, monounsaturated andpolyunsaturated fatty acids, displaying antioxidant activity, protection from cancer andhypertension, improvement of the immune response. Due to the presence of more thanone functional food groups in the same dietary pattern, sometimes in the same meal,diverse species of polyphenols as well as of phytosterols, fibers and fatty acids can becombined and activated. Next to the positive properties derived from the food, the physical activity also account for an important aspect of this life habits. In fact, sincelifestyle modification programs provide a method to change eating and activity habits,any diet intervention becomes more valid with a regular daily physical activity.The last element characterizing the Mediterranean diet is the perception of a meal asa moment to spend with other people and of food as a positive link. For all these complexand heterogeneous aspects, the Mediterranean diet has recently been named as"intangible cultural heritage by UNESCO"
Caco-2/HT-29 cell co-culture mimicking the intestinal barrier is a tunable model for gut aging
No full textConsidering the physiological role played by the intestinal epithelial barrier (IEB), the research related to modifications due to the microbiota and intestinal cell alterations with aging is attracting more and more attention. The necessity to standardize the appropriate experimental models is still unmet and is accompanied by a critical need to develop an in vitro study model of the IEB reproducing the interactions between the absorptive and the secreting cells related to aging.
The present study aimed at characterizing the morphology and the physiology of the aged IEB through an in vitro model constituted by a co-culture of the two cell lines Caco-2 and HT-29 that we previously differentiated and characterized in absorptive and mucus-secreting cells respectively1,2. The co-culture was set up by plating a 70/30 ratio mixture of differentiated Caco2 cells from the 24th to 50th passage and HT-29 cells from the 8th to 35th passages for inducing “physiological” aging, in the absence of any exogenous stimulus. In the aged co-culture set up by plating Caco-cells which had reached at least 40th sub cultivation passage and HT-29 the 21st passage, we observed relevant morphofunctional impairments as i) a diminished epithelial electrical resistance (TEER); ii) an increased paracellular permeability; iii) a slight decrease in cell proliferation; and iv) a less homogeneous distribution of the membrane-associated claudin-1 immunostaining. Transmission electron microscopy (TEM) analysis revealed that the intracellular mucus and desmosomes were less represented in the aged co-culture, together with underdeveloped apical microvilli. These results suggest that this experimental setting can reproduce some of the main morphofunctional modifications of IEB reported in clinics in the leaky/aged gut. Future experiments could ascertain the use of the aged in vitro Caco-2 and HT-29 cell co-culture as a useful model for studying the molecular process and testing potential drug/nutraceutical treatments to ameliorate gut aging
Nutritional knowledge in an Italian population of children, pre-adolescents and adolescents
No full textAbstract Objective To evaluate general knowledge about nutrition in an Italian population of children, pre-adolescents and adolescents. Design Knowledge about nutrition-related items such as healthy eating, breakfast, snacks, fast food, beverages, fruits and vegetables, cereals and tubers, meat/fish/legumes/eggs, milk and dairy products, fats and dressings, and sweets was analysed by means of a self-administered questionnaire (QuesCA IT) containing thirty-one questions, that was translated and adapted from a Swiss version (QuesCA) previously used in Geneva and Vaud. Setting North of Italy (Bergamo, Milan). Subjects Students (n 614) belonging to two different age groups: 9-11 years (GR1) and 12-16 years (GR2). Results Data analysis showed that nutritional knowledge varied in relation to the age of the participants, increasing in particular in the older group, although this difference was not statistically significant for all the considered items. Nutritional knowledge also varied in relation to the gender of the participants, with females in particular seeming to possess better cognition. For each age group there was poor knowledge about the items healthy diet, snacks, milk and dairy products, meat/fish/legumes/eggs, and fats and dressings. Moreover, the percentage of participants who declared own knowledge as insufficient was higher in GR2 compared with GR1. Conclusions The present research demonstrates a lack of knowledge about the main concepts of healthy nutrition both in the youngest and oldest participants of the survey. This evidence, together with the presence of higher self-consciousness in GR2, should be taken into account in specific educational interventions during the school period
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